Tie-tamper piston



Patented Bec. 20, i927. v

VQLLIAIV FRANK ZTMMERT'ANN, OF WAVERLY, NEW YORK, ASSIGNOR T0 INGERSOLL-RAND COMPANY, OF JERSEY CITY, vNEW' JERSEY5V A CORPORATON OF NEW.JERSEY.

TIE-Tarifen f rrsron.

Appiieation flied August e, 1926. Aseran Nn.`127,e1v7.

This invention relates to pneumatic percuss'ive tools and moreparticularly to the.

. YFigure l a longitudinal section of a,l

Vhammer tool constructed in accordance lwith the practice ofv theinvention,

Figure 2' is a longitudinal section through ythe piston of the hammertool,and

Figure 3 is a cross section through the piston7 taken along the line3-3. i Referring to the drawing,y the Vinvention is shown as applied toan .pneumatic tie tamper substantially as shown in U. S. Pat

ent No 1,470,622, granted to Francis A.

Jimerson V'October *16, 1923, comprising "a e cylinder A'within Awhich(a hammer piston B is adapted to reciprocate striking against' a tamperbar suitably supportedwithin a front head D.\ The tie tamper is guided'by a handle E having a pairV of grips F Vand G. The handle'Fi ispreferably provided with a flange H which is attached to a cylinderflange J bymeans of suitable bolts K.

The cylinder A is provided with two bores of different diameter7 thelarger bore L being at the rear end of the cylinderv and the smallerbore O being forward. P vis arranged to communicate with both bores Land O to conduct live motive fluid and exhaust to and from the rear boreL. To this end 'the larger bor-e L isprovided with two annular groovesQ, and R and the smaller bore O is provided with an annular groove S. Anexhaust port T is provided in an enlarged chamber Uforward of theborevO. I

The hammer piston B is ofthe differential type in which one area isconstantly eX- posed to line pressure of the motive fluid.

`Accordingly. the piston B isA provided with a head V of substantiallyythe diameter of the cylinder bore L and a tail portion W 'slidablyfitting the smaller cylinder bore 0.

The face `ofthepistfon headV adjacent the tail'portion W isconstantlyexposed to live pressure of Vmotive fluid entering thev cylin`der from an inlet port X inthe large bore L.

, Motive fluid `for driving the piston B forward is admitted to theannular port S from the forward end of the bore L by means of cut awayportions'of the tail por- .-rer,

tion VVV ofthe piston B in the form of lon* gitudinalgrooves Y somewhat'longer than the distancebetween thef'orward end 'of the bore L to theannular groove S. *Y

, The motive fluid distribution for actuat-A ing the'hammer piston lB isas follows. As-

` suming the piston B to start from'the posi` tion shown in Figure l,thepiston B .is

forced backwardlyfby pressure 'of motive fluid against the head V untilthe lon'fril tudinal grooves Y entertheflargerfbore The pressurein therear end of they boreQL is previously reduced to atmosphere `by freeaccess through theport P to the exhaust GLSv port Tjin the'chamber U.This exhaust .isi`

closed as the grooves Y are closed' bythe bore O. As" the groovesY'enterthe bore L motive `fluid is admitted tothe vportP and thencethrough 'annular groove` (i),v to the bore L. This g differential.pressure on opposite facesl ofthe piston head V drives the pistonv Bforward tostrike the steel C. This lcyclel ofoperations is repeatedindefinitely.y f l If the lpiston B is ybadly worn, motivek fluid` mayVleak past the 'piston head V into the upper bore so that the piston Bwill not start to reciprocate automatically; This may happen if thepiston B is very far forward so that grooves Y are closed to the Vpasstov atmosphere through the exhaust port T.

' The inlet portV X preferablycommunicates i .i

with a bore Z) .in aboss c on the cylinderVv wall A 'lorconnection withva throttle valve d.

The tainping bar C is held and guided in a pair, of sleeves e and ffitting snugly in a bore g of an extension 7L of the cylinder A. Thefront headrD acts as a Vretainei,"tlieie being a rubber butlerinterposed between the forward flange 7c of the front head D and theflanged sleeve f. The fronthead D is preferably bolted to a Harige o ofthe cylinder A. As is usual in tools of this Atype tHe shankoii the bai'C is provided with a colla-r p to retain the barv in the tooll and isafforded some movement by the spacing ofthe sleeves e and j Iclaimi ll.A pneumatic hammer tool comprising a cylinder, av differential typeVpiston* within said cylinder, an exhaust port at fone eiidoi' b ore,aport leading from the large bore to said cylinder, said piston beingprovided with cutaway portions to providefcommunication between the endsof the cylinder and a port through the piston leading `from one end ofsaid piston to the cut away portion to provide constant communication.from one endof the cylinder to the cut away portion of the'piston. g j2, A pneumatic hammer tool comprising a cylinder having a large bore andasmall the smaller bore, a piston adapted to reciprocate'vinsaidcylinder and having a head adapted to reciprocate in the large bore :anda vtail portion sliding in the'smaller cylinder A bore, an exhaustchamber in.

said y'cylinder adjacent the 'smaller cylin-l dery bore, cut awayiportions v in the tail portion of said piston ladapted to coop 'operate,with lsaid* port for connecting said port with said exhaust chainberandthe large b ore alternately, and a passage through said piston, thelarge bore being constantly in communication with said eut awayportions.

3; A pneumatic hammer tool comprising a i cylinder, a differential typepistonV within said cylinder, an exhaust port at one end of saidcylinder, said vpiston being provided ywith cutaway portions to providecommunication between the ends of the cylinder, and

a port providing'constant communication be-y u haust Jaseaee and saidexhaust 'fort anda port `providing constant communication be'- 'tweenone end of the cylinder and the space in thecylinder bore adjacent said'grooves in the piston.

5. A pneumatic hammer tool comprising a cylinder, a` diiilerential typepiston within the cylinder, an exhai'i'stv passage'- leading`r fromtlie'i'ear end of said cylinder to the cylinder bore interinediatetliecylinder ends,v

an exhaust port at one end oil" said cylinder, communication betweensaid exhaust pasm sage and exhaust portbeing controlled by the smallerend of differential type` pistoinf longitudinal grooves in said pistonto pro vide communication betweenfsaid exhaust passage and said exhaustport and'a port providing constant vcommunicati'on beti've'en one end ofthe cylinder and the space iii the cylinder bore .adjacent saidgroovesii: `ihe piston, saidv port being positioned infpis'ton. lntestimony wliefi'eoii have signed this specification. f Y u. l VILLIAMFRANK ZMMERMANN.

